Single crystal structure feature of a new 1D-coordination polymer of Mn (II); antioxidant activity and protective effects on BLC (both in enzyme activity and in structure)

Abstract

A new polymer of Mn (II) formulated as [(NIH) (Cl) Mn1 (µ-NIH)2 Mn2(Cl)) (H2O)2] [(NIH) (H2O) Mn3 (µ-NIH)2Mn4(H2O)3]n.6Cl·4H2ONIH, where NIH = 4-Pyridinecarboxylic acid hydrazide = Isoniazid = Isonicotinic acid hydrazide has been synthesized and characterized by elemental analysis, Fourier-transform infrared spectroscopy) FT-IR (, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Powder X-ray Diffraction(PXRD), and single crystal X-ray structure (SC-XRD). SC-XRD results revealed two 1D anionic coordination polymers which are accompanied by four water molecules, one isoniazid molecule, and six chlorine ions. Parallelepiped light orange crystals of Mn complex crystallize in a triclinic system with space group P1. Centers of Mn1, Mn2, Mn3, and Mn4 adopted slightly distorted octahedral. The antioxidant behavior of the Mn complex was tested through a DPPH assay and found that the Mn complex has a good performance in decolorizing the DPPH solution, so it reduces DPPH activity at a concentration of 50 mg L−1 to about 82%. Reactive oxygen species can cause oxidative stress in organisms. Catalase as a valuable antioxidant enzyme can play a protective role. Spectral techniques were used to investigate the effect of the Mn complex on the structure and function of bovine liver catalase (BLC). The catalytic activity of the BLC was significantly improved with the Mn complex. Fluorescence and CD results showed that this complex can induce the environmental changes of amino acid residues (especially Trp) and increase the stability of the secondary structure of the BLC by increasing the α-helix. The interaction process was spontaneous and exothermic, and the most important forces involved in it were van der Waals forces and hydrogen bonds.